Expanding the DWD network by Doppler lidar systems: evaluation of vertical wind profile measurements

Motivated by recent severe weather events Deutscher Wetterdienst (DWD) plans to expand its operational network by adding vertical profile measurements of wind and later also of humidity. The underlying aim is to spatially and temporally refine the observation base. As a consequence, short-term forecast and warning capabilities are expected to improve, in particular in case of extreme precipitation events.
In this context, a network of Doppler lidar systems will be installed at 13 automatic weather stations across Germany within the next two years. The sites have been selected in order to complement the existing DWD network of radiosonde stations, radar wind profilers and AMDAR measurements in the proximity of major airports. Doppler lidar systems are capable of estimating the three-dimensional wind vector in near real-time within the atmospheric boundary layer and (under appropriate conditions) up to a height of 12 km above ground level.
For a period of a few months, up to four of those future systems (WindCube 100S from Vaisala) are tested side-by-side on our test site in Hamburg, Germany. A StreamLine system (HALO Photonics by Lumibird) is added for cross-checking purposes.
Data from the instruments are used for detailed evaluation and comparison. This includes (1) the evaluation of potential alignment inaccuracies during on-site installation, (2) the variation among the instruments (regarding wind measurements and data availability), and (3) the evaluation and potential optimization of certain scan protocols. First results indicate an inter-instrument variation of considerably less than 2.0 m/s for the wind speed and of less than 10 degrees for the wind direction.